Buying your first pressed-powder compact is a coming-of-age moment, like a bar mitzvah or first kiss, or the day you realise God probably doesn't have a beard. It's such a grown-up thing. It's the non-screwcap wine of the cosmetics world, nice to show off. The good ones, such as Chanel's Mat Lumière (£34, 020 7493 3836), have a proper big mirror, so you can really get a handle on your T-zone shine in public, and a fine powder with a density that allows for layering – so as the day wears on and your face slips on a long bus ride, one swift pad to the forehead can make you look 9am again.